Background:: Oral mucosal lesions that are observed in the dermatological diseases are categorized under mucocutaneous conditions. The oral lesions in dermatological diseases may be the early aspects of the disease manifestation or the most significant clinical appearance or the only sign/and or symptom of such dermatological diseases and occasionally lesions occur simultaneously in the skin as well as mucous membrane. Aim:: This present study attempts to find out the prevalence of oral mucosal lesions in patients with dermatological diseases. Subjects and Methods:: The study includes 3500 patients who attended out-patient Department of Dermatology. Patients with oral manifestation were subjected for clinical examination in the Department of Oral Pathology. Diagnostic procedures were performed to confirm the clinical oral diagnosis. The results of the study were analyzed by SPSS software version 19.0 (Armonk, NY) and presented as descriptive statistics. Correlation of oral manifestions with their respective dermatological disease was statistically analysed by Pearson's correlation test.(P < 0.05 were considered as statistically significant) Results:: The prevalence rate of oral mucosal lesions in the present study was 1.8% (65/3500). The most frequent lesions observed were psoriasis 32.3% (21/65), lichen planus 18.4% (12/65), Stevens Johnson Syndrome 18.4% (12/65), pemphigus 10.7% (7/65), toxic epidermal necrolysis 4.6% (3/65), systemic lupus erythematosus 3% (2/65), discoid lupus erythematosus 1.5% (1/65), pemphigoid 1.5% (1/65). Gender distribution in the study population was statistically significant (P < 0.001). Employed and unemployed individuals in the study population were statistically significant (P < 0.001). Pearson's correlation analysis of oral manifestations with their respective dermatological disease showed r = 0.466 and signifies a positive correlation and is statistically significant at the 0.01 level (two-tailed). Conclusion:: The prevalence rate of oral mucosal lesions in patients with dermatological diseases was relatively low. However, predominant oral mucosal lesions observed in the study were autoimmune in origin with a high morbidity and mortality index. Hence, multidisciplinary approach will definitely help in the prognosis of patients.